This invention relates to tamper-proof closures, and, more particularly, to tamper-proof closures which are resealable.
A tamper-proof closure is one that provides a clear visual indication when it has been disturbed. Attempts have been made to provide a tamper-proof characteristic for closures to by using shrink fitting plastic sheeting. In order to open the closure it is necessary to remove the plastic sheeting which has been shrunk about the closure to act as a seal. Once the sheeting is destroyed the associated closure can be opened, but the protective material is no longer usable and must be discarded. In addition the use of shrinkable sheetings does not provide a clear visual indication of when the seal has been removed. Generally close scrutiny of the associated container is needed to verify that the seal has been broken.
In another attempt to provide a tamper resistant characteristic for closures, metallic caps have been provided with flanged skirts which are clamped to the lower lip of their associated containers. This kind of closure affords only a limited degree of protection against tampering since generally the skirted extension of the cap can be pried away from the associated lip, the cap opened, and then afterwards returned to its original position and the skirt repositioned against the lip of the container.
Another attempt to achieve a tamper-proof characteristic of closures has been attempted by using duplex plastic caps in which one part of the cap must be sheared away to obtain access to the contents of the container which makes use of the cap. Once the cap is sheared away the container requires a separate stopper for resealing, although the required shearing does achieve a degree of tamper resistance. There is, nevertheless, the objection that the duplex cap must be applied to its associated container and that the composite cap can often be removed so that the tamper-proof characteristic of the shearable upper portion can be frustrated by simply removing the entire cap.
Accordingly, it is object of the invention to facilitate the tamper-proof sealing of containers. A related object is to achieve tamper-proof sealing in which the tamper-proof portion of the closure cannot be either deliberately or accidentally removed from its associated container.
Another object of the invention is to achieve a tamper-proof seal in which there is a clear visual indication to the user of when the seal has been broken. A related object is to eliminate seals which provide tamper resistance but simultaneously fail to provide a clear indication of when the seal has been disturbed. Another related object is to eliminate the use of shrinkable sheet material in attempting to provide a tamper-proof characteristic for closures associated with containers.
Still another object of the invention is to provide a tamper-proof closure which can be resealed once the initial tamper-proof seal has been broken. A related object is to avoid the use of plastic seals, such as those associated with duplex closures, in which rupture of the initial seal prevents any reuse of the original closure and instead requires the procurement of an auxiliary closure once the initial seal has been disturbed. A related object is to eliminate the need for duplex closures which may be pried away or otherwise separated from their associated containers and thus defeat the desired tamper-proof characteristic that is being sought.